Zanchius quinquemaculatus Zou, 1987

Zanchius quinquemaculatus Zou, 1987 View in CoL

Figs 1 I, J View Figure 1 , 2 C, D, J – L, O View Figure 2

Zanchius quinquemaculatus Zou, 1987: 298, 300; Liu and Zheng 2014: 216. View in CoL

Specimen examined.

Vietnam • 1 ♂, Hoa Trung Lake , Hoa Lien Ward, Hoa Vang District, Da Nang City, 16.0891°N, 108.0425°E, 90 m altitude, on Mallotus barbatus , 2.xi.2024, J. Kim ( ZCDTU) ( DTUHMM 0040 ) GoogleMaps .

Diagnosis.

Recognized by greenish body with five orange-red markings; head width wide; long antennae, more than body length; first segment mostly orange-red, short, subequal to vertex; second segment entirely reddish brown; third segment long, subequal to second segment; apical part of third segment and fourth segment dark brown; pronotum entirely greenish brown, calli region distinctly swollen; apex of scutellum with orange-red spot; hemelytra entirely green except for four orange-red spots; middle part of clavus with two red-orange spots; subposterior part of corium with two red-orange spots; cuneus entirely green; membrane entirely greyish; vein with dark small spot apically; femur entirely green; pygophore with two long noticable projections; parameres large; left paramere trifurcated; right paramere long with one sharp process subapically, its hypophysis sharp; endosoma with two long and sinuate spiculi (Fig. 2 J – L, O View Figure 2 ).

Description.

Male: see the original description by Zou (1987). Genitalia: pygophore asymmetrical with two remarkable projections (Fig. 2 C, L View Figure 2 ); left paramere trifurcated, sensory lobe with two long projections, hypophysis sinuated, its apex curved and blunted (Fig. 2 J View Figure 2 ); right paramere long and curved, hypophysis sharp, with sharp process subapically (Fig. 2 K View Figure 2 ); endosoma with two long and sinuate spiculi (Fig. 2 O View Figure 2 ).

Female: not examined. According to Liu and Zheng (2014), one female specimen was examined without any comments, which may suggest no sexual dimorphism considering the unique and remarkable character of male.

Host.

Mallotus barbatus ( Euphorbiaceae ) *.

Distribution.

Vietnam (Central, Northern), China (Southeast, Southwest).

Remarks.

In the present study, the relatively long third antennal segment, subequal to the second segment, is identified as a diagnostic character of this species, despite most members of Zanchius typically exhibiting the longest second antennal segment. This conclusion is drawn notwithstanding the antennal segment measurement for Z. quinquemaculatus (antennal segment lengths = 0.25: 1.25: 0.8: 0.8) reported in the original description by Zou (1987), which differ from our observation. Furthermore, our direct examination revealed two spiculi in the endosoma, whereas only one spicule was described by Zou (1987). We infer that one spicule was overlooked in Zou’s (1987) description.

Notes on habitat sharing

In our investigation, the four species of the genus Zanchius were observed to be exclusively associated with the host plant Mallotus barbatus ( Euphorbiaceae ), which had been damaged solely by auchenorrhynchan species (Fig. 4 View Figure 4 ). This suggests that the presence of Zanchius species on the host plant may be linked to the damage caused by the phytophagous species, which likely serve as prey for these opportunists. While other plant species exhibited signs of damage from auchenorrhynchans, Zanchius species were found only on specific host plants where both the damage and the phytophagous insects were present. This may indicate a strong host plant association, in which damage by auchenorrhynchans plays a role in attracting Zanchius species, possibly due to the availability of prey or specific ecological conditions provided by these plants ( Messelink et al. 2012). Previous studies have reported that other Zanchius species (e. g. Z. tarasovi Kerzhner, 1988 ) are also found on host plants affected by auchenorrhynchan species, indicating that this association is not unique to the species observed in our study ( Yasunaga 1999).

Among the four species of the genus Zanchius observed in this study, Z. marmoratus was collected in significantly greater numbers compared to the other species and is known to have a wider geographical distribution. These findings suggest that Z. marmoratus may possess a competitive advantage over the other species when sharing the same host plant. Moreover, given the extensive distribution of the host plant, Mallotus barbatus (rainging from India to China), it is plausible that Z. marmoratus (or the genus Zanchius as a whole) has the potential for a broader geographic range.

While our observations confirm a strong association between the four Zanchius species and Mallotus barbatus , the possibility of a broader host plant range should not be overlooked. Some Zanchius species, including Z. tarasovi , have been documented on phylogenetically diverse plant lineages, which may suggest a connection to the zoophytophagous nature of the genus. Given this broader host association in other Zanchius species, the four species examined in this study may also utilize additional host plants, despite our current observations being limited to Mallotus barbatus . Further investigations are needed to determine the extent of their host plant flexibility and its ecological implications.